Electromagnetic actuators are being used more and more, to an increasing extent, in restraint devices for vehicles. Be it for activating rollover bars, headrests, or as a valve for cold gas generators. In the case of the valves for cold gas generators, it is frequently required that the corresponding airbags not be inflated all at once, but rather that the inflation of the airbags be adapted to the accident occurrence and the person to be protected, and that the airbags be filled more rapidly or more slowly. For this purpose, the gas supply is controlled over a certain period of, for example, approximately 50 ms, with an appropriate sequence of filling times and pause times.
German Patent Application No. DE 101 07 273 A1 describes a safety device for occupants of a vehicle and a method for controlling the safety device. The safety device includes at least one airbag which is fillable with a defined quantity of gas, a unit for supplying the quantity of gas to the airbag, and a control unit for activating the safety device. In this case, the instantaneous internal airbag pressure is controlled as a function of a vehicle deceleration and the progress of the internal airbag pressure over time.
A device and a method for controlling a continuous gas generator for inflating an airbag are described in German Patent Application No. DE 103 04 142 A1. In this case, the gas generator is controlled as a function of a linkage of crash features. In this case, in particular, a variable threshold is formed as a function of a crash severity and occupant characteristics. The device includes an electromagnetic actuator and an evaluation and control unit which generates at least one control signal as a function of a triggering decision which was reached, the control signal determining the chronological sequence of the control of the actuator and predefining a control sequence having at least one control time period, in which the actuator is activated, and at least one pause time period, in which the actuator is deactivated.